Method for forming end plate for heat exchanger and heat exchanger equipped with end plate formed with this method

ABSTRACT

A method for forming an end plate for a heat exchanger and a heat exchanger formed by this method are provided. The endplate is formed by preparing a concave die including a groove bottom surface and a pair of groove wall surfaces extending from both ends in the width direction of the groove bottom surface; preparing a convex die including a convex top surface facing the groove bottom surface of the concave die, convex wall surfaces facing the groove wall surfaces of the concave die, and protrusions provided along both sides in the width direction of the convex top surface; and inserting a plate member between the concave die and the convex die.

TECHNICAL FIELD

The present invention relates to a method for forming an end plate for a heat exchanger provided in a refrigerating circuit used in, for example, a vehicle air conditioning apparatus, and also relates to a heat exchanger equipped with end plates formed by this method.

BACKGROUND ART

Conventionally, there has been known a heat exchanger including: a pair of headers spaced from one another and extending in parallel with one another; a plurality of heat exchanger tubes spaced from each other in the header extending direction, each of the heat exchanger tubes being connected to the headers at both ends and; heat-transfer fins provided between adjacent heat exchanger tubes and also provided on the outer sides of the outer most heat exchanger tubes in the header extending direction; and end plates provided on the outer sides of the top and bottom heat-transfer fins, respectively, in the header extending direction, each of the end plates including a base part contacting the heat-transfer fin and extension parts extending from both sides in the width direction of the base part toward the outside of the header extending direction (see, for example, Patent literature 1).

This end plate for a heat exchanger is formed by press working including: inserting a plate member between a concave die and a convex die to bend the plate member, the concave die including a groove bottom surface and a pair of groove wall surfaces extending from both sides of the groove bottom surface, and the convex die including a convex top surface facing the groove bottom surface of the concave die and convex wall surfaces facing the groove wall surfaces.

CITATION LIST Patent Literature

-   PTL1: Japanese patent application Laid-Open No. 2003-94135

SUMMARY OF INVENTION Technical Problem

The end plate formed with the concave die and the convex die includes a bent portion between the base part and each of the extension parts which has a large radius of curvature, and therefore the width of the flat surface of the end plate facing the heat-transfer fin is smaller than the width of the heat-transfer fin. In addition, the end plate formed with the concave die and the convex die is connected to the adjacent heat-transfer fin by brazing. In this case, the area of the portion contacting the heat-transfer fin is small, and therefore the strength such as vibrational proof of the entire heat exchanger might be insufficient.

It is therefore an object of the present invention to provide a method for forming an end plate for a heat exchanger that can improve the strength such as vibration proof of the heat exchanger by increasing the area of the portion of the end plate contacting the adjacent heat-transfer fin, and also provide a heat exchanger equipped with end plates formed by this method.

Solution to Problem

To achieve the above-described object, the present invention provides a method for forming an end plate for a heat exchanger, the heat exchanger including: a pair of headers spaced from one another and extending in parallel with one another; a plurality of heat exchanger tubes spaced from each other in a header extending direction, each of the heat exchanger tubes being connected to the headers at both ends; heat-transfer fins provided between adjacent heat exchanger tubes and also provided on outer sides of outermost heat exchanger tubes in the header extending direction; and end plates provided on the outer sides of the top and bottom heat-transfer fins, respectively, in the header extending direction, each of the end plates including a base part contacting a heat-transfer fin and extension parts extending from both sides in a width direction of the base part toward an outside of the header extending direction, the method comprising: preparing a concave die including a groove bottom surface and a pair of groove wall surfaces extending from both ends in the width direction of the groove bottom surface; preparing a convex die including a convex top surface facing the groove bottom surface of the concave die, convex wall surfaces facing the groove wall surfaces of the concave die, and protrusions provided along both sides in the width direction of the convex top surface; and inserting a plate member between the concave die and the convex die to form an end plate. By this means, when the plate member is bent between the concave die and the convex die, the protrusions of the convex die push both sides in the width direction of the base part of the plate member to the concave die side. Therefore, it is possible to reduce the radius of curvature of the bent portion between the base part and each of the extension parts of the end plate, and consequently increase the width of the portion of the base part contacting the heat-transfer fin.

By this means, when the plate member bent between the concave die and the first convex die is inserted between the concave die and the second convex die, the portions corresponding to the extension parts are pushed by the convex base surface of the second convex die against the concave die. Therefore, it is possible to reduce the radius of curvature of the bent portion between the base part and the extension parts of the end plate, and consequently to increase the width of the portion of the base part contacting the heat-transfer fin.

By this means, when the plate member is bent between the concave die and the convex die, the plate member is bent at the grooves formed in the plate member. Therefore, it is possible to reduce the radius of curvature of the bent portion between the base part and each of the extension parts of the end plate, and consequently to increase the width of the portion of the base part contacting the heat-transfer fin.

According to the present invention, it is possible to reduce the radius of curvature of the bent portion between the base part and each of the extension parts of the end plate, and increase the width of the portion of the base part contacting the heat-transfer fin. By this means, it is possible to increase the area of the portion of the endplate connected to the heat-transfer fin by brazing, and therefore to improve the strength, rigidity, vibration proof and so forth of the heat exchanger.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view showing a refrigerant circuit according to Embodiment 1 of the present invention;

FIG. 2 is a front view showing a heat exchanger;

FIG. 3 is a perspective view showing an end plate;

FIG. 4 is a cross-sectional view showing the end plate;

FIG. 5 is a cross-sectional view showing dies and the end plate with a method for forming an end plate;

FIG. 6 is a cross-sectional view showing the dies and the end plate with the method for forming an end plate;

FIG. 7 is a cross-sectional view showing a die according to Embodiment 2 of the present invention;

FIG. 8 is a cross-sectional view showing dies and an end plate with a method for forming an end plate according to Embodiment 3;

FIG. 9 is a cross-sectional view showing the dies and the end plate with the method for forming an end plate;

FIG. 10 is a cross-sectional view showing the dies and the end plate with the method for forming an end plate;

FIG. 11 is a cross-sectional view showing the dies and the end plate with the method for forming an end plate;

FIG. 12 is a cross-sectional view showing the dies and the end plate with the method for forming an end plate;

FIG. 13 is a cross-sectional view showing dies and an end plate with a method for forming an end plate according to Embodiment 4; and

FIG. 14 is a cross-sectional view showing the dies and the end plate with the method for forming an end plate;

DESCRIPTION OF EMBODIMENTS

FIGS. 1 to 6 show Embodiment 1 of the present invention.

A heat exchanger equipped with an end plate according to the present invention is applicable to a refrigerating circuit used in a vehicle air conditioning apparatus. As shown in FIG. 1, this vehicle air conditioning apparatus includes a refrigerant circuit 1 to which an outdoor heat exchanger 10 provided outside a vehicle interior A is connected. In addition to the outdoor heat exchanger 10, a compressor 2 configured to compress a refrigerant, an indoor heat exchanger 3 provided in the vehicle interior A, and an expansion valve 4 configured to decompress the refrigerant are connected to the refrigerant circuit 1.

In the refrigerant circuit 1, the outdoor heat exchanger 10 is configured to release the heat from the refrigerant, and the indoor heat exchanger 3 is configured to absorb the heat into the refrigerant, so that cooling of the vehicle interior A is performed.

As shown in FIG. 2, the outdoor heat exchanger 10 includes: a pair of headers 11 (hereinafter may be referred to as “first header” and “second header”) extending in the vertical direction and spaced from one another in the width direction of the outdoor heat exchanger 10; a plurality of heat exchanger tubes 12 arranged in the vertical direction, each of which has one end connected to the first header 11 and the other end connected to the second header 11; a liquid receiver 13 connected to the header 11; a plurality of heat-transfer fins 14 provided between adjacent heat exchanger tubes and also provided on the outer sides of the top and bottom heat exchanger tubes 12 in the vertical direction; a pair of end plates 15 provided on the outer sides of the top and bottom heat-transfer fins, respectively, in the vertical direction; and brackets 16 provided on both sides in the longitudinal direction of each of the end plates 15.

Each of the headers 11 may be a hollow cylindrical member made of metal such as aluminum. The ends of the heat exchanger tubes 12 are connected to the outer periphery of each of the headers 11. The first header 11 includes a refrigerant inlet 11 a configured to flow the refrigerant discharged from the compressor 2 into the first header 11, and a refrigerant outlet 11 b configured to flow the refrigerant in the first header 11 out to the indoor heat exchanger 3. Meanwhile, the second header 11 includes a refrigerant outlet 11 c configured to flow the refrigerant in the second header 11 out into the liquid receiver 13, and a refrigerant inlet 11 d configured to flow the refrigerant having passed through the liquid receiver 13 into the second header 11. In addition, each of the headers 11 includes a plurality of partitions 11 e for dividing the inside of the header 11 in the vertical direction to determine the flow direction of the refrigerant flowing through the heat exchanger tubes 12. In FIG. 2, the refrigerant flowing from the refrigerant inlet 11 a into the first header 11 flows through heat exchanger tubes 12 a and flows into the second header 11. Then, the refrigerant flowing into the second header 11 via the heat exchanger tubes 12 a flows through heat exchanger tubes 12 b and flows into the first header 11. The refrigerant flowing into the first header 11 via the heat exchanger tubes 12 b flows through heat exchanger tubes 12 c, flows into the second header 11, and then flows into the liquid receiver 13 via the refrigerant outlet 11 c. The refrigerant having flowed into the liquid receiver 13 flows into the second header 11 via the refrigerant inlet 11 d, flows through heat exchanger tube 12 d, flows into the first headers 11, and flows out of the refrigerant outlet 11 b to the indoor heat exchanger 3.

Each of the heat exchanger tubes 12 is a tubular member, which is a hollow and flat plate, formed by extruding metal such as aluminum. Each of the heat exchanger tubes 12 are arranged such that the longitudinal direction (width direction) of the cross-section of its flow path matches the flow direction of the air subjected to a heat exchange with the refrigerant. In addition, by dividing the inside of each of the heat exchanger tubes 12 in the longitudinal direction (width direction) of the cross-section of the flow path, a plurality of refrigerant flow paths, as fluid flow paths through which the refrigerant flows, are formed in the heat exchanger tube 12 in the longitudinal direction (width direction) of the cross-section of the flow path.

The liquid receiver 13 is a metallic member made of, for example, aluminum, and is formed in a cylindrical shape closed at both ends. The liquid receiver 13 is disposed such that its central axis extends in the vertical direction like the headers 11, and is connected to the second header 11 via the refrigerant outlet 11 c and the refrigerant inlet 11 d. A dryer and a filter are accommodated in the liquid receiver 13. The drier removes water from the refrigerant flowing into the liquid receiver 13, and the filter catches foreign materials such as dust in the refrigerant flowing into the liquid receiver 13.

Each of the heat-transfer fins 14 is formed with a corrugated plate member made of metal such as aluminum, and attached to the heat exchanger tube 12 and the end plate 15 by brazing.

Each of the end plates 15 is formed by pressing a metallic pate 15′ which is made of, for example, aluminum and has a brazing filler metal layer. As shown in FIGS. 3 and 4, the end plate 15 includes a base part 15 a extending in the longer direction of the end plate 15, and extension parts 15 b extending approximately orthogonally from both sides in the shorter direction of the base part 15 a, except both ends in the longer direction of the base part 15 b. The end plate 15 is formed by pressing the metallic plate 15′ having a thickness T of 1.5 mm. As a result, the end plate 15 has a width W1 of 12 mm, the flat portion of the base part 15 a facing the heat-transfer fin 14 has a width W2 of 9.5 mm, and the bent portion between the base part 15 a and each of the extension parts 15 b has a radius of curvature R of 2 mm. The end plate 15 is connected to each of the headers 11 at both ends in its longitudinal direction, and fixed to the headers 11 by brazing. In addition, the heat-transfer fin 14 is connected to the base part 15 a of the end plate 15 by brazing.

The brackets 16 are attached to the end plate 15 between the extension parts 15 b by welding, riveting, swaging and so forth, and are fixed to the end plate 15 by brazing. The brackets 16 are fixed to a member, for example, in the engine room outside the vehicle interior A by fastener members such as bolts and nuts. The outdoor heat exchanger 10 is mounted in the engine room via the brackets 16.

In the refrigerant circuit 1 including the heat exchanger having the above-described configuration, when the compressor 2 is driven, the refrigerant discharged from the compressor 2 releases the heat in the outdoor heat exchanger 10, is decompressed via the expansion valve 4, absorbs the heat in the indoor heat exchanger 3, and is sucked into the compressor 2.

Now, a method for forming the end plate 15 will be described with reference to FIGS. 5 and 6. The end plate 15 is formed by pressing the flat metallic plate 15′ with a concave die 21 and a convex die 22.

The concave die 21 is formed as a groove and has a flat groove bottom surface 21 a and groove wall surfaces 21 b extending from both sides of the groove bottom surface 21 a.

Meanwhile, the convex die 22 is a projection and has a convex top surface 22 a facing the groove bottom surface 21 a and convex wall surfaces 22 b facing the groove wall surfaces 21 b. Protrusions 22 c are provided on the convex top surface 22 a to extend along the both sides of the convex top surface 22 a. Each of the protrusions 22 c has a rectangular cross-section having a width W3 of 0.5 mm and a height H of 0.3 mm.

When pressed by the concave die 21 and the convex die 22, the flat metallic plate 15′ is bent to form the base part 15 a and the pair of extension parts 15 b, so that the end plate 15 is completed. When the metallic plate 15′ is pressed by the concave die 21 and the convex side 22, the protrusions 22 c of the convex die 22 contacts the both sides of the base part 15 a and pushes the contacting portions to the concave die 21 as shown in FIG. 6. Therefore, the radius of curvature of the bent portion between the base part 15 a and each of the extension parts 15 b of the end plate 15 in the concave die 21 is smaller than when the metallic plate 15′ is pressed with a die without the protrusions 22 c. In addition, the width of the flat surface of the base part 15 a in the concave die 21 side is greater than when the metallic plate 15′ is pressed with a die without the protrusions 22 c.

As described above, the method for forming an endplate for a heat exchanger according to the present embodiment forms the endplate 15 by: preparing the concave die 21 including the groove bottom surface 21 a and the pair of groove wall surfaces 21 b extending from both sides of the groove bottom surface 21 a; preparing the convex die 22 including the convex top surface 22 a facing the groove bottom surface 21 a of the concave die 21, the convex wall surfaces 22 b facing the groove wall surfaces 21 b of the concave die 21, and the protrusions 22 being provided along both sides in the width direction of the convex top surface 22 a; inserting the metallic plate 15′ between the concave die 21 and the convex die 22. By this means, it is possible to reduce the radius of curvature of the bent portion between the base part 15 a and each of the extension parts 15 b of the end plate 15, and increase the width W2 of the flat surface of the base part 15 a contacting the heat-transfer fin 14. Therefore, it is possible to increase the area of the portion of the endplate 15 connected to the heat-transfer fin 14 by brazing, and therefore to improve the strength, rigidity, vibration proof and so forth of the heat exchanger 10.

Moreover, the end plate 15 is formed with a plate member including a brazing filler metal layer. By this means, the grooves formed by the protrusions 22 c of the convex die 22 during the press working can be covered with molten brazing filler metal during the brazing. Therefore, it is possible to prevent the strength of the end plate 15 from being reduced due to the grooves formed by the protrusion 22 c during the press working.

FIG. 7 shows Embodiment 2 of the present invention. The same components as the components in Embodiment 1 are assigned the same reference numerals.

With the present embodiment, protrusions 22 d are provided on the convex top surface 22 a of the convex die 22 to extend along the both ends in the width direction of the convex top surface 22 a. Each of the protrusions 22 d has a triangular cross-section having the width W3 of 0.5 mm and the height H of 0.3 mm. The vertex of the protrusion 22 d lies in the same plane as or inside the convex wall surface 22 b.

When the flat metallic plate 15′ is pressed with the concave die 21 and the convex die 22 configured as described above, the radius of curvature of the bent portion between the base part 15 a and each of the extension parts 15 b of the end plate 15 in the concave die 21 side is smaller than when the metallic plate 15′ is pressed with a die without the protrusions 22 d, in the same way as Embodiment 1. In addition, the width of the flat surface of the base part 15 a in the concave die 21 side is greater than when the metallic plate 15′ is pressed with a die without the protrusions 22 d.

As described above, the method for forming an endplate for a heat exchanger according to the present embodiment can reduce the radius of curvature of the bent portion between the base part 15 a and each of the extension parts 15 b of the end plate 15, and increase the width W2 of the flat surface of the base part 15 a contacting the heat-transfer fin 14, in the same way as Embodiment 1. Therefore, it is possible to increase the area of the portion of the endplate 15 connected to the heat-transfer fin 14 by brazing, and therefore to improve the strength, rigidity, vibration proof and so forth of the heat exchanger 10.

FIGS. 8 to 12 show Embodiment 3 of the present invention. Here, the same components as the components in the previous embodiments are assigned the same reference numerals.

With the present embodiment, the end plate 15 is formed by: pressing the flat metallic plate 15′ between the concave die 21 and a first convex die 23; and further pressing this pressed plate member between the concave die 21 and a second convex die 24 having a shape different from the first convex die 23.

The first convex die 23 is a projection and has a convex top surface 23 a facing the groove bottom surface 21 a and convex wall surfaces 23 b facing the groove wall surfaces 21 b.

The second convex die 24 is a projection and has a convex top surface 24 a facing the groove bottom surface 21 a, convex wall surfaces 24 b facing part of the groove wall surfaces 21 b, and convex base surfaces 24 c each of which extends outward in the width direction from the convex wall surface 24 b at the position spaced from the convex top surface 24 a by a predetermined distance and faces the groove bottom surface 21 a.

When pressed with the concave die 21 and the first convex die 23, the flat metallic plate 15′ is bent on both sides in the width direction, and therefore is formed in a U-shape in cross-section as shown in FIG. 9. In addition, when this metallic plate 15′ having a U-shape in cross-section is pressed with the concave die 21 and the second convex die 24, the base part 15 a and the pair of extension parts 15 b are formed, so that the end plate 15 is completed. When the metallic plate 15′ is pressed with the concave die 21 and the second convex die 24, the convex base surfaces 24 c of the second convex die 24 abuts on the surfaces of both ends of the U-shape of the metallic plate 15′, and portions to be the extension parts 15 b are pushed to the concave die 21 as shown in FIG. 11. Therefore, the radius of curvature of the bent portion between the base part 15 a and each of the extension parts 15 b of the end plate 15 in the concave die 21 side is smaller than before the metallic plate 15′ is pressed with concave die 21 and the second convex die 24. In addition, the width of the flat surface of the base part 15 a in the concave die 21 side is greater than before the metallic plate 15′ is pressed with concave die 21 and the second convex die 24.

As described above, the method for forming an end plate for a heat exchanger according to the present embodiment forms the end plate 15 by: preparing the concave die 21 including the groove bottom surface 21 a and the pair of groove wall surfaces 21 b extending from both ends in the width direction of the groove bottom surface 21 a; preparing the first convex die 23 including the convex top surface 23 a facing the groove bottom surface 21 a and the convex wall surfaces 23 b facing the groove wall surfaces 21 b; inserting the metallic plate 15′ between the concave die 21 and the first convex die 23 to bend the metallic plate 15′; and preparing the second convex die 24 including the convex top surface 24 a facing the groove bottom surface 21 a, the convex wall surfaces 24 b facing part of the groove wall surfaces 21 b, and the convex base surfaces 24 c each of which extends outward in the width direction from the convex wall surface 24 b at the position spaced from the convex top surface 24 a by a predetermined distance and faces the groove bottom surface 21 a; and inserting the metallic plate 15′ having been bent by the concave die 21 and the first convex die 23, between the concave die 21 and the second convex die 24 while the surfaces of both ends of the bent metallic plate 15′ abuts on the convex base surfaces 24 c, so that the end plate 15 is completed. By this means, it is possible to reduce the radius of curvature of the bent portion between the base part 15 a and each of the extension parts 15 b, and increase the width W2 of the flat surface of the base part 15 a contacting the heat-transfer fin 14. Therefore, it is possible to increase the area of the portion of the end plate 15 connected to the heat-transfer fin 14 by brazing, and therefore to improve the strength, rigidity, vibration proof and so forth of the heat exchanger 10.

FIGS. 13 and 14 show Embodiment 4 of the present invention. Here, the same components as the components in the previous embodiments are assigned the same reference numerals.

With the present embodiment, the endplate 15 is formed by: forming a pair of grooves 15 c in the width direction of the flat metallic plate 15′ by press working, cutting and so forth; and pressing the metallic plate 15′ having the grooves by using the concave die 21 and a convex die 25. Here, the pair of grooves 15 c in the width direction is formed in the metallic plate 157 at or near the bent portion between the base part 15 a and the respective extension parts 15 b of the end plate 15.

The concave die 21 is formed as a groove and has the flat groove bottom surface 21 a and the groove wall surfaces 21 b extending vertically from the both ends in the width direction of the groove bottom surface 21 a.

The convex die 25 is a projection, and has a convex top surface 25 a facing the groove bottom surface 21 a and convex wall surfaces 25 b facing the groove wall surfaces 21 b.

When pressed with the concave die 21 and the convex die 22, the flat metallic plate 15′ is bent to form the base part 15 a and the pair of extension parts 15 b, so that the end plate 15 is completed. When pressed with the concave die 21 and the convex die 22, the metallic plate 15′ is bent at the grooves 15 c. Therefore, the radius of curvature of the bent portion between the base part 15 a and each of the extension parts 15 b of the end plate 15 in the concave die 21 side is smaller than when the metallic plate 15′ without the groves 15 c is pressed. In addition, the width of the flat surface of the base part 15 a in the concave die 21 side is greater than when the metallic plate 15′ without the grooves 15 c is pressed.

As described above, the method for forming an endplate for a heat exchanger according to the present embodiment forms the endplate 15 by: preparing the concave die 21 including the groove bottom surface 21 a and the pair of groove wall surfaces 21 b extending from both ends in the width direction of the groove bottom surface 21 a; preparing the convex die 25 including the convex top surface 25 a facing the groove bottom surface 21 a and the convex wall surfaces 25 b facing the groove wall surfaces 21 b of the convex die 21; and inserting the metallic plate 15′ with the pair of grooves 15 c in the width direction of the metallic plate 15′ between the concave die 21 and the convex die 25. By this means, it is possible to reduce the radius of curvature of the bent portion between the base part 15 a and each of the extension parts 15 b of the end plate 15 and increase the width W2 of the flat surface of the base part 15 a contacting the heat-transfer fin 14. Therefore, it is possible to increase the area of the portion of the end plate 15 connected to the heat-transfer fin 14 by brazing, and therefore to improve the strength, rigidity, vibration proof and so forth of the heat exchanger 10.

In addition, the endplate 15 is formed with a plate member including a brazing filler metal layer. By this means, the grooves 15 c formed before the press working can be covered with the molten brazing filler metal during the brazing, and therefore it is possible to prevent the strength of the end plate 15 from being reduced due to the grooves 15 c formed before the press working.

With the above described embodiments, the method for forming the end plate 15 for the outdoor heat exchanger 10 for heat release in a vehicle air conditioning apparatus has been described. However, it is by no means limiting. The present invention is applicable to any heat exchanger not for a vehicle air conditioning apparatus as long as the heat exchanger includes an end plate. Moreover, the present invention is not limited to a heat exchanger for heat release, but is applicable to a heat exchanger for heat absorption, or a heat exchanger which can switch between heat release and heat absorption.

REFERENCE SIGNS LIST

10 outdoor heat exchanger, 11 header, 12 heat exchanger tube, 14 heat-transfer fin, 15 end plate, 15′ metallic plate, 15 a base part, 15 b extension part, 15 c groove, 21 concave die, 21 a groove bottom surface, 21 b groove wall surface, 22 convex die, 22 a convex top surface, 22 c protrusion, 23 first convex die, 24 second convex die, 24 c convex base surface 

1. A method for forming an end plate for a heat exchanger, the heat exchanger including: a pair of headers spaced from one another and extending in parallel with one another; a plurality of heat exchanger tubes spaced from each other in a header extending direction, each of the heat exchanger tubes being connected to the headers at both ends; heat-transfer fins provided between adjacent heat exchanger tubes and also provided on outer sides of outermost heat exchanger tubes in the header extending direction; and end plates provided on the outer sides of the top and bottom heat-transfer fins, respectively, in the header extending direction, each of the end plates including a base part contacting a heat-transfer fin and extension parts extending from both sides in a width direction of the base part toward an outside of the header extending direction, the method comprising: preparing a concave die including a groove bottom surface and a pair of groove wall surfaces extending from both ends in the width direction of the groove bottom surface; preparing a convex die including a convex top surface facing the groove bottom surface of the concave die, convex wall surfaces facing the groove wall surfaces of the concave die, and protrusions provided along both sides in the width direction of the convex top surface; and inserting a plate member between the concave die and the convex die to form an end plate.
 2. A method for forming an end plate for a heat exchanger, the heat exchanger including: a pair of headers spaced from one another and extending in parallel with one another; a plurality of heat exchanger tubes spaced from each other in a header extending direction, each of the heat exchanger tubes being connected to the headers at both ends; heat-transfer fins provided between adjacent heat exchanger tubes and also provided on outer sides of top and bottom heat exchanger tubes in the header extending direction; and end plates provided on the outer sides of the top and bottom heat-transfer fins, respectively, in the header extending direction, each of the end plates including a base part contacting a heat-transfer fin and extension parts extending from both sides in a width direction of the base part toward an outside of the header extending direction, the method comprising: preparing a concave die including a groove bottom surface and a pair of groove wall surfaces extending from both ends in the width direction of the groove bottom surface; preparing a first convex die including a convex top surface facing the groove bottom surface of the convex die and convex wall surfaces facing the groove wall surfaces of the concave die; inserting a plate member between the concave die and the first convex die to bend the plate member; preparing a second convex die including a convex top surface facing the groove bottom surface of the concave die, concave wall surfaces facing the groove wall surfaces of the concave die, and convex base surfaces each of which extends outward in the width direction from a convex wall surface at a position spaced from the convex top surface by a predetermined distance and faces the groove bottom surface of the concave die; and inserting the plate member having been bent by the concave die and the first convex die, between the concave die and the second convex die while the surfaces of both ends of the bent plate member abuts on the convex base surfaces to form an end plate.
 3. A method for forming an end plate for a heat exchanger, the heat exchanger including: a pair of headers spaced from one another and extending in parallel with one another; a plurality of heat exchanger tubes spaced from each other in a header extending direction, each of the heat exchanger tubes being connected to the headers at both ends; heat-transfer fins provided between adjacent heat exchanger tubes and also provided on outer sides of top and bottom heat exchanger tubes in the header extending direction; and end plates provided on the outer sides of the top and bottom heat-transfer fins, respectively, in the header extending direction, each of the end plates including a base part contacting a heat-transfer fin and extension parts extending from both sides in a width direction of the base part toward an outside of the header extending direction, the method comprising: preparing a concave die including a groove bottom surface and a pair of groove wall surfaces extending from both ends in the width direction of the groove bottom surface; preparing a convex die including a convex top surface facing the groove bottom surface of the concave die and convex wall surfaces facing the groove wall surfaces of the concave die; preparing a plate member having a pair of grooves formed in the width direction of the plate member; and inserting the plate member between the concave die and the convex die.
 4. The method according to claim 1, wherein the end plate is formed with the plate member including a brazing filler metal layer.
 5. A heat exchanger comprising an end plate formed by the method according to claim
 1. 6. The method according to claim 2, wherein the end plate is formed with the plate member including a brazing filler metal layer.
 7. The method according to claim 3, wherein the end plate is formed with the plate member including a brazing filler metal layer.
 8. A heat exchanger comprising an end plate formed by the method according to claim
 2. 9. A heat exchanger comprising an end plate formed by the method according to claim
 3. 10. A heat exchanger comprising an end plate formed by the method according to claim
 4. 11. A heat exchanger comprising an end plate formed by the method according to claim
 5. 12. A heat exchanger comprising an end plate formed by the method according to claim
 6. 